This invention relates generally to the field of automatic fastening devices and associated methods, and more particularly but not by way of limitation to an apparatus and associated method suited for continuous flexible fabrication processes involving installing fasteners in a variety of work pieces by biasing the work piece in operable engagement with a replaceable datum member corresponding to the work piece.
To be competitive, manufacturers generally have transitioned from batch processing of parts and assemblies to just-in-time processing approaches. Maximum throughput requires speed and flexibility in each step of the manufacturing process. But these two objectives, speed and flexibility, can be mutually exclusive. For example, dedicated tooling, or hard tooling, approaches optimize machine utilization but negatively affect flexibility. Conversely, flexible tooling, or soft tooling, approaches optimize flexibility but negatively affect velocity through the manufacturing process. Typically, the complexity and volume of a component or assembly determines whether hard or soft tooling approaches, or some combination thereof, best supports the throughput requirement.
Fastener attachment is an example of a manufacturing assembly process where there is a long-felt need for improvement. More traditional solutions have involved locating a work piece to be joined with fasteners in a carrier, or fixture, and indexing or conveying the work piece operably adjacent the fastening tool. In this arrangement, the carrier establishes the datum references for the work piece. That is, the carrier orients the work piece so as to define the fastener positions. The fastening tool is configured to install the fasteners at the positions predetermined by the carrier. Maintaining the datum is relatively critical for a fastener install operation, especially with regard to threaded fastener operations where the screw must engage the corresponding fastener receptacle squarely for a proper threading engagement. Maintaining the datum by the carrier complicates several aspects such as the carrier design, the picking and placing of work pieces to and from the carrier, and the movement of the carrier between manufacturing operations.
More recent solutions involve relaxing the datum requirement of the carrier and providing smart tool approaches that can relatively determine the fastener receptacle position. U.S. Pat. No. 4,562,756 issued to Otsuki et al., for example, describes the use of a moveable fastening tool responsive to an ultrasonic detector which can detect the fastener receptacle. This type of solution is relatively complex, expensive, and slow especially with regard to the fine positioning movement of the carrier and/or the fastening tool in response to the detector devices.
It has been determined that a simpler and faster solution lies in establishing the datum by a datum member portion of the assembly machine instead of the carrier. The work piece can be roughly positioned by the carrier and finely positioned by moving the work piece from the carrier, or with the carrier, into operable engagement with the datum member. By making the datum member easily removable and replaceable with a different datum member, a variety of different work pieces can be processed. It is to this and other improvements as exemplified by the description and appended claims that embodiments of the present invention are directed.
The embodiments of the present invention contemplate an apparatus and associated method for installing a fastener to a fastener receptacle portion of a work piece. In one aspect of the embodiments of the present invention an automatic fastener apparatus comprises a central frame supporting a datum member. The datum member defines a fastener position, and the datum member is operably engageable with a characteristic feature of the work piece. The fastener apparatus further comprises a fastening tool supported by the frame and moveable to the fastener position. The fastener apparatus further comprises a biasing member biasing the work piece characteristic feature in operable engagement with the datum member aligning the fastener receptacle with the fastener position.
The work piece can consist of one or more component parts to be joined by the fastener, and a carrier containing the components. In one embodiment the datum member operably engages a characteristic feature of the carrier. Preferably, the datum member is removably attached to the frame, such as by a threaded fastener, making the fastener apparatus convertible for use with a variety of work pieces.
The fastening apparatus can further comprise a programmable controller controlling the fastening tool movement, and controlling a conveyor moving the work piece into the frame.
In one embodiment the fastener apparatus datum member comprises a fixed locating pin operably engageable with a characteristic feature of the work piece. In one embodiment the fastener apparatus datum member comprises a fixed locating pin operably engageable with a characteristic feature of the carrier. In one embodiment the fastener apparatus datum member comprises a retractable locating member operably engageable with a characteristic feature of the work piece.
In one aspect of the embodiments of the present invention a method is contemplated for automatically attaching a fastener to a fastener receptacle portion of a work piece, comprising: providing a fastening apparatus comprising a fastening tool moveable relative to a datum member defining a fastener position; moving the fastening tool to the fastener position; biasing the work piece in operable engagement with the datum member to align the fastener receptacle with the fastener position; and activating the fastening tool to engage the fastener within the fastener receptacle.
These and various other features as well as advantages which characterize the present invention will be apparent upon a reading of the following detailed description and review of the associated drawings.